Hawks' mass migration puts natural aerodynamics to work

I could not help but notice the statuesque broad-winged hawk perched on a limb of an aspen tree along Route 447 in Price Township recently.

I could not help but notice the statuesque broad-winged hawk perched on a limb of an aspen tree along Route 447 in Price Township recently.

Feeling lucky at the chance to capture a photo of the raptor, I drove to the very next intersection, pulled off the road and quickly gathered my camera and telephoto lens. I then turned the car around and drove back toward the hawk. Luckily, the hawk remained on sentry and did not alight when I parked my car on the shoulder of the road across from the raptor.

It appeared that the broad-winged hawk paid no attention to my presence and was interested in capturing its next meal. The raptor remained motionless as it focused intently on the grassy vegetation below — perhaps a meadow vole or eastern garter snake lurked beneath.

The hawk's persistent behavior allowed me to focus my camera lens on its feathered frame and capture several nice photos.

It was an adult broad-winged hawk about the size of a crow. The bird of prey displayed beautiful plumage with rusty-brown horizontal patterns across its snow-white chest. Dark brown feathers covered the head, and its long tail was banded in white and black. Supporting its streamlined frame were two legs colored a brilliant yellow-orange and powerful talons painted jet black.

The broad-wing's eyes were an intense reddish-yellow. Its sharply hooked bill was black, but the most eye-catching feature was the upper bill or cere, which was a vibrant yellow-orange.

Broad-winged hawks are in the Buteo genus, which exhibit broad wings and tails and are capable of soaring flight. Broad-winged hawks breed in vast deciduous or mixed forests throughout the eastern United States and southern Canada. They are relatively abundant throughout the Pocono Mountains and are the smallest among the three Buteo species — red-shouldered and red-tailed are the other two — that breed in our region.

After a few minutes, the broad-winged hawk became alerted to the sudden movements of my camera lens and alighted from the limb. In no time at all, it had unfolded its 3-foot wingspan and black- and white-banded tail and soared gracefully in the sky. The hawk circled several times overhead and screeched a high-pitched, strident "pitz-zeeeeeeeeee" then glided out of sight.

It was a fascinating aerial display that I had just witnessed, but what's even more amazing is the fact that by mid-September, practically every broad-winged hawk in Canada and the eastern United States will partake in a spectacular migration thousands of miles to South America.

Thousands upon thousands of broad-wing hawks will vacate the northeastern part of the continent in a matter of a few weeks. Likewise, thousands of hawk watchers migrate to hawk-watch sites to witness this spectacular spectacle of September.

World-renowned hawk-watch sites such as Hawk Mountain in Kempton will have parking lots over-filled with eager spectators — now turn cliff-hangers — anxious to witness the miracle of migration.

What the hawk watchers hope to see are large "kettles" of broad-wing hawks floating above their heads.

The broad-wing hawk has figured out a way to migrate thousands of miles southward using the least amount of energy. The hawks take advantage of air currents, which provides effortless modes of aerial transportation — thermal currents and deflective currents.

On hot, calm, sunny days after a cool September evening, the sun heats the ambient air in a special way. The morning sun heats the terrain, and warm air rises into the atmosphere. Broad-wing hawks target these thermal currents as the warm rising air provides that extra boost to help lift or keep afloat broad-winged hawks.

When conditions are just right, thousands of broad-winged hawks join together and form a large "kettle," which resembles a slow-motion, feathery tornado.

The hawks float upward nearly several thousand feet, then break free from the kettle and glide for miles until they enter the next solar-charged thermal.

The second means of hawk migration is deflective currents, in which prevailing wind deflects upward against a cliff or mountain ridge. The deflective winds provide updraft that hawks utilize as energy-efficient means of migration. They do not form large, floating kettles but use their aerodynamic body shape and glide for long distances quite rapidly, like a surfer riding a huge wave.

There are several phenomenal hawk-watch sites found throughout the region. Try to plan a visit, as you won't be disappointed.

Most hawk-watch sites are stationed with official hawk counters who will graciously share their expertise with novice hawk watchers. They also welcome the extra set of eyes or binoculars.

If you cannot visit a hawk-watch site, you still have a chance to witness the mass exodus. Try to spend a mid-morning moment, lunch or break outside the home, office or automobile and venture into a parking lot, local park or shopping mall.

Face the northeast and keep your eyes high in the sky. I have often observed impressive kettles of broad-wing hawks this way as well as soaring bald eagles, ospreys and falcons. Just think, in a few more weeks you'll be singing, "I Love Those Lazy, Hazy, Crazy Days of September."

To learn more about hawk migration or find a hawk-watch site near you, visit:

hawkmountain.org hawkcount.org hmana.org/sitesel.php hawkwatch.org

Contact Rick Koval at pocononaturalist@yahoo.com or write to him at PO Box 454, Dallas, PA 18612.